This invention relates to a track-type vehicle undercarriage.
In the conventional undercarriages of the kind specified, upper rails each carrying multi-rollers mounted on an endless track are fixedly secured, respectively, to a bracket fitted to a bearing part of an idler, and therefore as the length of the upper rails becomes longer, a larger moment M is exerted on the supporting part.
In general, as the length of the upper rails becomes longer, the distance between the upper rails becomes shorter. If the sag of the endless track is kept at the same value, the tension on the track will reduce resulting in a reduced running resistance; however, as mentioned above, a larger moment M is exerted on the supporting part.